Self-curing artificial fingernails

ABSTRACT

Self-curing artificial fingernail compositions containing crosslinking monomers, monoacrylates and suitable initiators and accelerators, and methods of polymerizing and applying same.

This application is a continuation of our earlier patent applicationSer. No. 665,214, filed Mar. 9, 1976, now abandoned, which in turn was acontinuation of our earlier patent application, now abandoned, Ser. No.527,221, filed Nov. 26, 1974.

BACKGROUND

While the advent of artifical fingernails was greeted with exceptionalenthusiasm, complications since experienced have significantly dampenedthe enthusiasm. The most popular and widely-used artifical fingernailcompositions have been two-part (liquid/powder) formulations wherein theliquid portion usually consists of methyl methacrylate monomer and asmall amount of a polymerization accelerator or promoter, such as atertiary amine, and the powder portion generally consists of polymethylmethacrylate and a catalyst, such as benzoyl peroxide.

In situ polymerization is effected by mixing a small amount of theliquid portion with a small amount of the powder portion on the end of abrush, and the mixture brushed on the nail surface to be repaired,protected or elongated. Elongation requires affixing a substrate meansto the exposed edge of the nail, which means has the general contour ofthe natural nail and extends therefrom to the desired length and alongthe plane of the natural nail. The substrate is preferably of a materialto which the polymerized mixture does not adhere. In this way it may beremoved following construction of the artificial nail.

Blending the powder/liquid portions, as by brushing, results in at leasta part of the powder dissolving in the liquid monomer, and the monomerpolymerizes simultaneously through the action of the accelerator andcatalyst. The mixing and brushing steps are repeated as often as neededto form the desired thickness and nail form. When polymerization iscompleted, the artificial nail may then be smoothed, shaped and a nailpolish applied if desired.

As is well known, natural nails (fingernails and toenails) are afflictedwith may problems related to health, accidents and abuse. For example,various genetic and disease-related abnormalities may disrupt nailgrowth, texture, thickness and strength, thus promoting fingertip injuryand unsightliness. Accidents occur to produce nail damage, such astearing, splitting, breaking and scarring. Likewise, nails are abused byso-called "nail-biters". There being no real medical solutions to theseproblems, the advent of artificial fingernails of the aforementionedtype was a most welcome development.

Unfortunately, however, the fingernail preparations just described arenot without serious inherent drawbacks and disadvantages. Importantamong these disadvantages is the fact that the principal constituent ofthe liquid portion, methyl methacrylate, is a low molecular weight,volatile compound with a penetrating, unpleasant odor. In fact, methylmethacrylate monomer has been shown to cause severe dermatologcalreactions, cardiovascular irregularities and other ailments. Althoughthe prepolymerized powder appears safe in these formulations, thepolymerization of monomer which proceeds in situ after mixing powder andliquid is far from complete, because of the nature of the reactant.Consequently, unreacted methyl methacrylate is available to causedermatitis and other ailments.

Another disadvantage present formulations have is that the presence ofunreacted low molecular weight methyl methacrylate in the matrix of theresulting polymer structure weakens same and generally leads not only toan artificial fingernail polymer of low mechanical strength, brittlenessand lack of flexibility, but also leads to a lack of reproducibility ofproperties due to variations in the completeness of polymerization.

Another disadvantage of present formulations rests in the fact that theyproduce a high exotherm during polymerization, in some cases requiringthat fingers be cooled in water following application.

A further disadvantage of present formulations is the time-consumingnature of the applicaton process, which in part is a result of poorapplication qualities of the material, and in part a result of excessivetime needed in finishing the nail because of the poor mechanical qualityof the artificial nail.

It follows from the above-noted multiple disadvantages that there is adefinite need for artificial nails which can be applied with greatersafety and which exhibit greater strength, greater impact resistance,greater flexibility, greater processability, greater reproducibility,and lower exotherm during polymerization. The present invention not onlyfills this need but further provides even better wear resistance,retention, resistance to chemical solutions and moisture. In short, thecompositions of instant discovery at once obviate the serious drawbackshereinbefore discussed and provide superior physical, mechanical andcosmetic properties. As such, they are directed to the "cosmeticulous".

The following references, of varying degrees of relevance, wereuncovered in a recent study of the artificial fingernail art: U.S. Pat.Nos. 2,073,867, H. A. Feigenbaum; 2,688,331, B. Bogoslowsky; 2,941,535,R. J. Lappe; 2,979,061, J. Greenman et al; 2,633,139, H. L. Pettey;3,037,514, M. M. Lappe; 3,157,912, D. Lisczawka; 3,425,426, F. P.Welanetz; 3,478,576, Sautter et al; 3,483,289, J. B. Michaelson;3,487,831, M. Jaume et al; 3,502,088, S. Jarby; 3,553,401, J. M.Michaelson; 3,574,822, Thomas H. Shepherd et al; 3,645,835, M. E.Hodgson; Chemical Abstracts, Vol. 61, page 1704(f) Cosmetics, Scienceand Technology, September 16, 1957, pages 693-716.

INVENTION

The present invention concerns artificial nail compositions comprising,by weight, (a) from about 5% to about 80%, preferably about 10% to about80%, of an aromatic, cycloaliphatic or aliphatic crosslinking monomercontaining at least two groups able to polymerize in the presence of aperoxide-type initiator (catalyst) and a tertiary amine-type accelerator(promoter), (b) from 0 to about 60%, preferably less than about 45%, ofa monoacrylate monomer, (c) a peroxide-type initiator, and (d) atertiary amine-type accelerator. More particularly, the instantdiscovery relates to artificial nail compositions, of the type and inthe concentrations just described, in which the initiator, such asbenzoyl peroxide, is present in the concentration of about 0.2% to about4.0%, by weight, and the accelerator, such as N,N-dimethyl-p-toluidine,is present in the concentration of about 0.1% to about 8.0% by weight.Generally, but not necessarily, a polymeric filler, such as apolyacrylate, is present in the composition, as will be seenhereinafter.

Among the crosslinking monomers herein contemplated are2,2bis[4'(-3"-methacryloyl-2"-hydroxypropoxy)phenyl] propane, mono-,di-, tri-, tetra-, and polyethylene glycol dimethacrylates; diallylfumarate, 2,2bis (4'-methacryloyl phenyl) propane, 2,2 bis(4'-methacryloylethyloxyphenyl) propane, diallyphthalate,butene-diol-1,4-dimethacrylate, allylmethacrylate,bis(2-methacryloylethyl) o-, m-, and p- phthalates,2-acryloylethylmethacrylate.

Other similar crosslinking monomers having at least two groups ormoieties, such as allyl, acryloyl, methacryloyl or other similarunsaturations, capable of polymerizing in the presence of the initiatorsand accelerators of the present invention are herein contemplated.Typically, these monomers are not only mono-polymerizable, so to speak,and co-polymerizable but they are suitable crosslinking agents foracrylic polymers.

Typical monoacrylates (acrylic and methacrylic esters) within thepurview of the present invention are (1) substituted or unsubstituted,lower alkyl or alkenyl (C₁ -C₅) and cycloalkyl methacrylates, includingbut not limited to methyl methacrylate, ethyl methacrylate, propylmethacrylate, butyl methacrylate, hydroxyethyl methacrylate, glycidylmethacrylate, cyclohexyl methacrylate and cyclopentyl methacrylate,tetrahydrofurfurylmethacrylate, and (2) substituted or unsubstituted,lower alkyl or alkenyl (C₁ -C₅) and cycloalky acrylates, including butnot limited to methyl acrylate, ethyl acrylate, propyl acrylate, butylacrylate, hydroxyethyl acrylate, glycidyl acrylate,tetrahydrofurfurylacrylate, cyclopentyl acrylate and cyclohexylacrylate. Obviously, substitutent moieties other than hydroxy and epoxywhich do not interfere with or significantly disrupt the intendedpolymerization reaction are herein contemplated.

As suggested hereinabove, it has been found pursuant to the instantdiscovery that, quite surprisingly, the superior results hereinbeforedescribed may be achieved and the likewise heretofore-mentioneddrawbacks may be avoided using the crosslinking monomers alone or inadmixture, as taught supra, with the monoacrylates. For best results,when combining the crosslinking monomers with the monoacrylates, theformer are present in a concentration of at least 5% of the weightconcentration of monoacrylate or monoacrylates. Of course, blends ofcrosslinking monomers and blends of monoacrylates may be employed ifdesired.

Of the initiators herein contemplated, the preferred are thefree-radical catalysts, such as the organic peroxides and particularlybenzoyl peroxide and lauroyl peroxide.

The accelerators within the purview of the instant discovery andpreferred are the tertiary amines, especiallyN,N-di(lower)alkyl-p-toluidines (e.g., N,N-dimethyl-p-toluidine,N,N-diethyl-p-toluidine) and N,N-di (lower) alkyl anilines, such asN,N-dimethyl aniline.

Of course, other conventional free-radical catalysts and promoters,while not at present preferred, may be used in lieu of or in conjunctionwith (when compatible) the foregoing.

The set time for the compositions of the present invention, usuallyabout 120 to about 400 seconds, may be regulated by varying theconcnetration of initiators and/or accelerators. Inorganic fillers, suchas finely-divided alumina silicates, silica, quartz, glass, and thelike, may be used to control consistency of material and improve itsphysical and mechanical properties.

Generally, as suggested hereinbefore, a polymeric filler material whichmay be soluble, partially soluble or insoluble in the resin matrix ispresent. Typically, but not necessarily, these are polymers orcopolymers of the monomeric materials used in the in situ polymerizationcomposition. Suitable for and very effective in the compositions of thepresent invention are copolymeris of ethyl and methyl methacrylate,polyethyl methacrylate, polymethyl methacrylate, polymethyl acrylate,polyethyl acrylate and polypropyl acrylate. In other words, polymers ofthe monoacrylates herein contemplated are suitable.

The just-mentioned fillers are usually present in a concentration ofless than about 60%, preferably from about 5% to about 55%, by weight.

Minor conventional amounts of modifiers may also be present, such asdyes, opaquing agents (e.g., titanium dioxide), and stabilizers (e.g.,3-butyl-4-hydroxytoluene).

According to another embodiment of the present invention, it has beenfound that the flexibility of the aforementioned cured fingernailcompositions is significantly enhanced by incorporationg in theprecursor polymerizable composition from about 2 to about 20%, byweight, of esters of aromatic compounds, such as mono-, di-, tri- andpoly- ethylene glycol dibenzoates, lower alkyl (C₁ -C₅) phthalates ordiphthalates, and cycloalkylphthalates or cycloalkyldiphthalates, e.g.,cyclopentylphthalate, cyclohexylphthalate, cyclopentyldiphthalate, andcyclohexyldiphthalate.

The concentrations given herein are based upon the combined wiehgt(100%) of all of the components which are blended to make up the finalcomposition. Of course, it is appreciated that in situ polymerization ispreferably carried out by blending two-part formulations (e.g.,liquid/powder portions). Upon blending both formulations, the resultingmixture contains the individual components in concentrations within theranges hereinabove recited. For convenience, however, the weightconcentration of each component in each of the examples, infra, isrecited as a percentage of the individual formulation, i.e., part A orpart B.

The ratio of the parts, i.e., the ratio of part A to part B, may varyfrom about 3:1 to about 1:3, depending upon the application propertiesdesired, so long as the component concentrations in the resultingmixture are within the range herein recited. The 3:1 to 1:3 combinationmixes well, flows well and gives a satisfactory degree of color andtranslucency for most nails. It cures reliably, with a reproducible settime and superior and reproducible physical and mechanical properties.On the basis of dermatological testing performed on a number of women,the compositions herein contemplated have acceptable properties.

EXAMPLES

The present invention will be more fully described by reference to thefollowing examples which illustrate certain preferred embodiments of thepresent invention.

EXAMPLES I

    ______________________________________                                                            Percent by Weight                                         ______________________________________                                        Part A (Powder)                                                               70/30 copolymer of ethyl and                                                  methyl methacrylate   99.1                                                    benzoyl peroxide (catalyst)                                                                         0.8                                                     titanium dioxide (opaquing agent)                                                                   0.1                                                     Part B (Liquid)                                                               methyl methacrylate   78.35                                                   polyethylene glycol dimethacrylate                                                                  20.0                                                    dimethyl-p-toluidine (accelerator)                                                                  1.0                                                     2-hydroxy-4-methoxy benzophenone                                              (UV-absorber)         0.5                                                     3-butyl-4-hydroxy toluene (stabilizer)                                                              0.05                                                    dye                   0.1                                                     ______________________________________                                    

Typical physical properties of the cured composition are as follows:

    ______________________________________                                        Hardness, Shore D       88                                                    Compressive strength, psi                                                                             10,600                                                Flexural strength, psi  10,700                                                Flexural modulus, psi   16,000                                                ______________________________________                                    

In this example and in the examples which follow, both parts (be theyliquid/powder or paste/paste) are applied separately and mixed on thenail. Of course, it can be appreciated that alternatively both parts maybe pre-mixed immediately before application on the nail or substrateelongator.

In Examples I-V the ratio of A to B, as applied is 1:1.

EXAMPLE II

    ______________________________________                                                            Percent by Weight                                         ______________________________________                                        Part A (Powder)                                                               70/30 copolymer of ethyl                                                      and methyl methacrylate                                                                             50.4                                                    polymethyl methacrylate                                                                             48.4                                                    benzoyl peroxide (catalyst)                                                                         1.0                                                     titanium dioxide (opaquing                                                    agent)                0.2                                                     Part B (Liquid)                                                               methyl methacrylate   60.0                                                    cyclohexyl methacrylate                                                                             15.5                                                    triethylene glycol dimethacrylate                                                                   22.85                                                   dimethyl-p-toluidine                                                          (accelerator)         1.0                                                     2-hydroxy-4-methoxy-                                                          benzophenone (UV-absorber)                                                                          0.5                                                     3-butyl-4-hydroxytoluene                                                      (stabilizer)          0.05                                                    dye                   0.1                                                     ______________________________________                                    

EXAMPLE III

    ______________________________________                                                            Percent by Weight                                         ______________________________________                                        Part A (Powder)                                                               polymethyl methacrylate                                                                             98.7                                                    benzoyl peroxide (catalyst)                                                                         1.0                                                     titanium dioxide (opaquing agent)                                                                   0.3                                                     Part B (Liquid)                                                               methyl methacrylate   30.5                                                    ethyl methacrylate    35.0                                                    allyl methacrylate    5.0                                                     BIS/GMA*              3.0                                                     50-50 mixture of di- and tri-                                                 ethylene glycol dimethacrylates                                                                     23.9                                                    N-bis (2-hydroxyethyl)-p-                                                     toluidine (accelerator)                                                                             2.0                                                     2-hydroxy-4-methoxy-                                                          benzophenone (UV absorber)                                                                          0.5                                                     3-butyl-4-hydroxy toluene                                                     (stabilizer)          0.1                                                     ______________________________________                                         *2,2 bis[4'(-3"-methacryloyl-2"-hydroxypropoxy)phenyl]propane            

EXAMPLE IV

It has been found possible, as illustrated in this example, to formulatethese ingredients as a two-paste system rather than a powder-liquidsystem. The same superior qualities are realized in the two-paste systemas in the powder-liquid system. In addition, application is faster andsmoother. The two pastes are preferably mixed in a ratio of 1:1.

    ______________________________________                                                            Percent by Weight                                         ______________________________________                                        Part A (Paste)                                                                ethyl methacrylate    50.9                                                    polyethylene glycol dimethacrylate                                                                  10.7                                                    triethylene glycol dibenzoate                                                                       7.0                                                     sub-micron synthetic crystalline                                              silica                21.1                                                    N,N-dimethyl-p-toluidine                                                      (accelerator)         1.1                                                     3-butyl-4-hydroxytoluene                                                                            0.19                                                    dye                   0.01                                                    Part B (Paste)                                                                ethyl methacrylate    59.2                                                    polyethylene glycol dimethacrylate                                                                  10.5                                                    triethylene glycol dibenzoate                                                                       7.0                                                     sub-micron synthetic crystalline                                              silica                21.0                                                    3-butyl-4-hydroxytoluene (stabilizer)                                                               0.2                                                     benzoyl peroxide (catalyst)                                                                         2.1                                                     ______________________________________                                    

EXAMPLE V

    ______________________________________                                                            Percent by Weight                                         ______________________________________                                        Part A (Powder)                                                               70/30 copolymer of ethyl and                                                  methyl methacrylate   99.1                                                    benzoyl peroxide (catalyst)                                                                         0.8                                                     titanium dioxide (opaquer)                                                                          0.1                                                     Part B (Liquid)                                                               2-hydroxyethyl methacrylate                                                                         72.1                                                    polyethylene glycol                                                           dimethacrylate        21.25                                                   triethylene glycol dibenzoate                                                                       5.0                                                     N,N-dimethyl-p-toluidine                                                      (accelerator)         1.0                                                     2-hydroxy-4-methoxy-                                                          benzophenone (UV-absorber)                                                                          0.5                                                     3-butyl-4-hydroxytoluene                                                                            0.05                                                    (stabilizer)                                                                  dye                   0.1                                                     ______________________________________                                    

Typical physical properties of the cured polymer are as follows:

    ______________________________________                                        Hardness, Shore D       86                                                    Compressive strength, psi                                                                             13,000                                                Flexural strength, psi  7,200                                                 Flexural modulus, psi   14,000                                                ______________________________________                                    

As indicated hereinabove, in Examples I-V the ratio of A to B, asapplied, is 1:1.

EXAMPLE VI

    ______________________________________                                                            Percent by Weight                                         ______________________________________                                        Part A (Powder)                                                               polymethyl methacrylate                                                                             90.0                                                    colloidal silica      9.1                                                     benzoyl peroxide (catalyst)                                                                         0.9                                                     Part B (Liquid)                                                               polyethyleneglycoldimethylacrylate                                                                  98.3                                                    N,N-dimethyl-p-toluidine                                                                            1.0                                                     2-hydroxy-4-methoxybenzophenone                                               (UV absorber)         0.5                                                     3-butyl-4-hydroxytoluene                                                      (stabilizer)          0.1                                                     dye                   0.1                                                     ______________________________________                                    

In Example VI the ratio of A to B, as applied according to Example I, is2:1.

EXAMPLE VII

    ______________________________________                                                            Percent by Weight                                         ______________________________________                                        Part A (Powder)                                                               70/30 copolymer of ethyl                                                      methylmethacrylate    80.0                                                    polymethylmethacrylate                                                                              19.0                                                    benzoyl peroxide (catalyst)                                                                         0.9                                                     titanium dioxide (opaquer)                                                                          0.1                                                     Part B (Liquid)                                                               tetrahydrofurfurylmethacrylate                                                                      85.9                                                    diallyphthalate       5.0                                                     diethylene glycol dimethacrylate                                                                    8.0                                                     N,N-dimethyl-p-toluidine                                                                            1.0                                                     hydroquinone (stabilizer)                                                                           0.05                                                    dye                   0.05                                                    ______________________________________                                    

In Example VII the ratio of A to B, as applied according to Example I,is 1:3.

EXAMPLE VIII

    ______________________________________                                                            Percent by Weight                                         ______________________________________                                        Part A (Powder)                                                               70/30 copolymer of ethyl                                                      and methyl methacrylate                                                                             50.4                                                    polymethyl methacrylate                                                                             48.4                                                    benzoyl peroxide (catalyst)                                                                         1.0                                                     titanium dioxide (opaquing                                                    agent)                0.2                                                     Part B (Liquid)                                                               tetrahydrofurfurylmethacrylate                                                                      88.35                                                   diethylene glycol dimethacrylate                                                                    10.00                                                   N,N bis(2-hydroxyethyl)-p-toluidine                                                                 1.0                                                     2-hydroxy-4-methoxy-benzophenone                                              (UV absorber)         0.5                                                     3-butyl-4-hydroxytoluene                                                      (stabilizer)          0.05                                                    dye                   0.1                                                     ______________________________________                                    

In Example VIII the ratio of A to B, as applied according to Example I,is 1:1.

Pursuant to statuatory requirements there are described above theinvention and what are now considered its best embodiments. It should beunderstood, however, that the invention can be practiced otherwise thanas specifically described, within the scope of the appended claims.

What is claimed is:
 1. A self-curing, dermatologically acceptablecomposition to be applied to a natural nail as a hardenable coating orto form an artificial nail, which composition consists essentially of amixture of the following ingredients, by weight based on the totalweight of the composition:(a) from about 5% to about 80% of a firstaddition polymerizable, ethylenically unsaturated monomer that can forma cross-linked polymer upon polymerization during self-curing of thecomposition, which monomer contains in its molecule at least two groupsthat are capable of being addition polymerized upon contact with aperoxide-type free radical initiator and a tertiary amine-typeaccelerator, the polymerizable groups being members of the groupconsisting of allyl, acryloyl, methacryloyl, or combinations thereof;(b) a second monomer that is monoethylenically unsaturated, in an amountup to about 60%, that copolymerizes with the first monomer uponself-curing of the composition to form a copolymeric structure that iscross-linked, the second monomer being either tetrahydrofurfurylacrylate or tetrahydrofurfuryl methacrylate; (c) a peroxide-type freeradical initiator; (d) a tertiary amine-type accelerator; and (e) fromabout 5% to about 60% of a polymeric filler that is at least partiallysoluble in the composition;the composition being formulated and theinitiator and the accelerator being present in a quantity to causeself-curing to occur in situ within about 120 to about 400 seconds aftermixture of the ingredients and application to a nail, under ambientconditions to which the nail is normally exposed including ambienttemperature and the presence of atmospheric oxygen.
 2. A composition inaccordance with claim 1 wherein the second monomer is present in a minoramount, less than 45% by weight of the composition.
 3. A composition inaccordance with claim 2 wherein the initiator is present in an amount inthe range from about 0.2% to about 4%, and the accelerator is present inan amount from about 0.1% to about 8%, the percentages being by weightof the composition.
 4. A composition in accordance with claim 3 whereinthe polymeric filler is soluble in the composition and is present in anamount from about 5% to about 55% by weight of the composition.
 5. Acomposition in accordance with claim 4 including from about 2% to about20% by weight of the composition of an aromatic ester as a flexibilizingmaterial.
 6. A composition in accordance with claim 1 wherein the (a)monomer is selected from the group consisting of 2,2 bis[4'(3'-methacryloyl-2"-hydroxypropoxy)phenyl]propane; mono-, di-, tri-,tetra-, and polyethylene glycol dimethacrylates; diallyl fumarate; 2,2bis (4'-methacryloyl phenyl) propane; 2,2 bis(4'-methacryloylethyloxy-phenyl) propane; diallyl phthalate;butenediol-1,4,-dimethacrylate; allyl methacrylate; bis(2-methacryloylethyl) o-, m-, and p-phthalates;2-acryloylethylmethacrylates, and mixtures thereof.
 7. A composition inaccordance with claim 3 wherein the (a) monomer is polyethylene glycoldimethacrylate.
 8. A composition in accordance with claim 5 wherein the(a) monomer is triethylene glycol dimethacrylate.
 9. A composition inaccordance with claim 5 wherein the (a) monomer is a mixture of allylmethacrylate; bis-GMA, and a mixture of diethylene glycol andtriethylene glycol dimethacrylates.
 10. A composition in accordance withclaim 5 wherein the (a) monomer is a mixture of diallyl phthalate anddiethylene glycol dimethacrylate.
 11. A composition in accordance withclaim 5 wherein the (a) monomer is diethylene glycol dimethacrylate. 12.A self-curing, dermatologically acceptable composition to be applied toa natural nail as a hardenable coating or to form an artificial nail,which composition consists essentially of a mixture of the followingingredients, by weight based on the total weight of the composition:(a)from about 5% to about 80% of a first addition polymerizable,ethylenically unsaturated cross-linkable monomer selected from the groupconsisting of 2,2bis [4'(3"-methacryloyl-2"-hydroxy-propoxy) phenyl]propane; mono-, di-, tri-, tetra-, and polyethylene glycoldimethacrylates; diallyl fumarate; 2,2 bis (4'-methacryloyl phenyl)propane; 2,2 bis (4'-methacryloylethyloxy-phenyl) propane; diallylphthalate, butenediol-1, 4-dimethacrylate; allyl methacrylate,bis(2-methacryloylethyl) o-, m-, and p-phthalates;2-acryloylethylmethacrylates; and mixtures thereof; (b) a second monomerthat is monoethylenically unsaturated, in an amount to about 45%, thatcopolymerizes with the first monomer upon self-curing of the compositionto form a copolymeric structure that is cross-linked, said secondmonomer being either tetrahydrofurfuryl acrylate or tetrahydrofurfurylmethacrylate; (c) from about 0.2% to about 4.0% of a peroxide-type freeradical initiator; (d) from about 0.1% to about 8.0% of a tertiaryamine-type accelerator; (e) from about 5% to about 55% of a polymericfiller that is at least partially soluble in the composition; and (f)from about 2% to about 20% of an aromatic ester as a flexibilizingmaterial;the composition being formulated and the initiator andaccelerator being present in a quantity to cause self-curing to occur insitu without about 120 to about 400 seconds after mixing the ingredientsand application to a nail, under ambient conditions to which the nail isnormally exposed including ambient temperature and the presence ofatmospheric oxygen.
 13. A composition suitable to be applied to afingernail as a hardenable coating or to form an artificial nail, whichcomposition consists essentially of a mixture of the followingingredients, by weight based on the total weight of the composition;(a)from about 5% to about 80% of a cross-linkable monomer selected from thegroup consisting of ethylene glycol dimethacrylate, diethylene glycoldimethacrylate, triethylene glycol dimethacrylate, polyethylene glycoldimethacrylate, and mixtures thereof, that are capable of beingpolymerized upon contact with a peroxide-type free radical initiator anda tertiary amine-type accelerator; (b) a minor amount up to about 45% oftetrahydrofurfuryl methacrylate, (c) from about 0.2% to about 4.0% ofbenzoyl peroxide; (d) from about 0.1% to about 8.0% of a tertiaryamine-type accelerator; (e) from about 5% to about 55% of a polymericfiller that is at least partially soluble in the composition; and (f)from about 2% to about 20% of a flexibilizing material;the initiator andthe accelerator being present in a quantity to cause curing to occurwithin about 120 to about 400 seconds after mixing the ingredients,under ambient conditions to which the nail is normally exposed includingambient temperature and the presence of atmospheric oxygen.